Re: MOS 8565 VIC-II

From: Laze Ristoski (
Date: 2003-04-30 11:48:47

> Now suppose you write 0 to $d021 in an infinite loop.  The sparkles should
> appear in the text area.

Exactly, but not on the border this time. In case you write to $d022, dots
will only appear in ECM mode on a char that uses $d022 background.

> I call them sparkles, because on my C128, their
> width varies from about half a pixel to a full pixel.

Hmmm.... That's probably why one of my chips give
blurry dots, while the others give sharp dots.

> > Aren't there any sparkle-free VICs for C128?
> I'm not aware of any.

Probably no line-free as well. :)

> Do the sparkles disappear completely on your machine?

Yes. I often test with a simple loop from basic. Sometimes the
screen is overfilled with dots, sometimes they are rare, and sometimes
they completely disappear. That also happens in programs I know
to have sparkling problems. Sometimes they simply work like on 6569. :)

> Try producing vertical
> sparkle bars by writing a 63- or 65-cycle loop of sta $d020 on a blank
> screen.

Just did that. Yeps! They disappear completely.
I have tested several chips, and they disappeared of two of them.
(one MOS and one CSG).

> The analog parts of the new VIC run off 9 volts while the old VIC needs 12
> volts.

So 9V is insufficient for the 6569.

> If I remember correctly, Andreas Boose told me that the new VIC
> overheats but works in the old C64.

And it's impossible, vice versa.

> Do it on your own risk. :-)

Nooo, thanks! :-)


ps. Just noticed that two of my C64Cs are having
power-up problems. When I swtich the C64 on,
sometimes the screen is not black, but having chars
like when you reset it. After this the C64 works normally.
Any idea what would be the problem?

       Message was sent through the cbm-hackers mailing list

Archive generated by hypermail pre-2.1.8.